The Berkeley Evolution Site
The Berkeley site offers resources that can help students and teachers understand and teach evolution. The resources are organized into optional learning paths for example "What does T. rex look like?"
Charles Darwin's theory of natural selection explains how creatures that are better equipped to adapt biologically to a changing environments over time, and those that don't disappear. Science is all about this process of evolutionary change.
What is Evolution?
The term "evolution" could have many nonscientific meanings. For example it could mean "progress" and "descent with modifications." Scientifically it is a term used to describe a changing the characteristics of living things (or species) over time. The reason for this change is biological terms on natural selection and drift.
Evolution is a fundamental concept in modern biology. It is a well-supported theory that has stood up to the tests of time and thousands of scientific tests. Evolution doesn't deal with spiritual beliefs or God's presence like other theories of science, such as the Copernican or germ theory of diseases.
Early evolutionists, such as Jean-Baptiste Lamarck and Erasmus Darwin (Charles's grandfather) believed that certain physical traits were predetermined to change in a step-like way, over time. This was known as the "Ladder of Nature" or scala naturae. Charles Lyell first used this term in 1833 in his Principles of Geology.
Darwin published his theory of evolution in his book On the Origin of Species published in the early 1800s. It states that all species of organisms share an ancestry that can be traced through fossils and other evidence. This is the modern view of evolution, and is supported by many lines of scientific research, including molecular genetics.
Scientists do not know the evolution of organisms but they are sure that natural selection and genetic drift is responsible for the development of life. People with desirable traits are more likely to survive and reproduce. They pass on their genes on to the next generation. As time passes the gene pool slowly changes and develops into new species.
Some scientists also use the term"evolution" to refer to large-scale evolutionary changes, such as the formation of a new species from an ancestral species. Others, like population geneticists, define the term "evolution" more broadly by referring to the net variation in the frequency of alleles over generations. Both definitions are acceptable and precise however some scientists believe that the allele-frequency definition is missing crucial aspects of the evolutionary process.
Origins of Life
A key step in evolution is the appearance of life. The emergence of life occurs when living systems start to develop at a microscopic scale, for instance within cells.
The origins of life is an issue in a variety of disciplines such as geology, chemistry, biology and chemistry. The question of how living organisms began has a special place in science due to it being a major challenge to the theory of evolution. It is often referred to as "the mystery of life" or "abiogenesis."
Traditionally, the idea that life could emerge from nonliving things is known as spontaneous generation, or "spontaneous evolution." This was a popular belief prior to Louis Pasteur's experiments proved that it was impossible for the creation of life to be a result of a purely natural process.
Many scientists still believe it is possible to make the transition from nonliving materials to living. The conditions required to create life are difficult to replicate in a laboratory. Researchers who are interested in the evolution and origins of life are also eager to learn about the physical characteristics of the early Earth as well as other planets.
The growth of life is dependent on a number of complex chemical reactions that are not predicted by the basic physical laws. These include the reading and the replication of complex molecules, such as DNA or RNA, to produce proteins that serve a specific function. These chemical reactions are comparable to the chicken-and-egg issue: the emergence and development of DNA/RNA, protein-based cell machinery, is required to begin the process of becoming a living organism. However without 무료 에볼루션 , the chemistry required to enable it is working.
Research in the field of abiogenesis requires collaboration among scientists from a variety of disciplines. This includes prebiotic scientists, astrobiologists and planet scientists.
Evolutionary Changes
The term "evolution" today is used to describe gradual changes in genetic traits over time. These changes could be the result of adapting to environmental pressures, as described in Darwinism.
This latter mechanism increases the frequency of genes that offer the advantage of survival for an animal, resulting in an overall change in the appearance of a group. These evolutionary changes are caused by mutations, reshuffling of genes during sexual reproduction and gene flow.
Natural selection is the process that allows beneficial mutations to become more common. All organisms undergo mutations and reshuffles of genes. As previously mentioned, those who possess the desirable trait have a higher reproduction rate than those that do not. This differential in the number of offspring produced over a long period of time can result in a gradual change in the average number advantageous traits in the group.
This is evident in the evolution of different beak shapes on finches from the Galapagos Islands. They have developed these beaks so they can get food more easily in their new habitat. These changes in the form and shape of organisms can also help create new species.
The majority of changes are caused by a single mutation, however sometimes multiple occur simultaneously. Most of these changes are neither harmful nor even harmful to the organism however, a small proportion of them can have an advantageous impact on survival and reproduction, thus increasing the frequency of these changes in the population over time. Natural selection is a process that causes the accumulating change over time that leads to the creation of a new species.
Some people confuse evolution with the idea of soft inheritance which is the notion that traits inherited from parents can be changed by conscious choice or by abuse. This is a misinterpretation of the nature of evolution, and of the actual biological processes that cause it. It is more accurate to say that the process of evolution is a two-step, separate process, that is influenced by the forces of natural selection as well as mutation.
Origins of Humans
Modern humans (Homo sapiens) evolved from primates, a group of mammals that also includes chimpanzees and gorillas and bonobos. The earliest human fossils prove that our ancestors were bipeds, walkers on two legs. Genetic and biological similarities suggest that we are closely related to chimpanzees. In reality, our closest relatives are the chimpanzees from the Pan genus. This includes pygmy as well as bonobos. The last common ancestor between modern humans and chimpanzees was 8 to 6 million years old.
Humans have evolved a variety of characteristics over time such as bipedalism, use of fire and advanced tools. It is only in the past 100,000 years or so that most of the traits that distinguish us from other species have been developed. These include a big brain that is complex, the ability of humans to create and use tools, as well as cultural variety.
The process of evolution occurs when genetic changes allow members of the group to better adapt to their environment. This adaptation is driven by natural selection, a process that determines certain traits are more desirable than others. The ones who are better adapted are more likely to pass on their genes to the next generation. This is how all species evolve, and the basis for the theory of evolution.
Scientists call it the "law of Natural Selection." The law states that species which have a common ancestor are likely to develop similar traits over time. This is because the traits allow them to live and reproduce in their natural environment.
All organisms possess the DNA molecule, which contains the information needed to guide their growth. The DNA molecule is made up of base pairs that are spirally arranged around phosphate molecules and sugar molecules. The sequence of bases within each string determines the phenotype or the appearance and behavior of an individual. Variations in a population can be caused by reshufflings and mutations of genetic material (known collectively as alleles).
Fossils of the first human species, Homo erectus and Homo neanderthalensis have been discovered in Africa, Asia, and Europe. These fossils, despite some differences in their appearance, all support the theory that modern humans' ancestors originated in Africa. The fossil and genetic evidence suggests that the first humans left Africa and moved to Asia and Europe.